Preparation of advanced CCMs for AMFCs by amination and cross-linking of the precursor form of the ionomer

Abstract

In an AMFC, in the formation of a CCM, the anode catalyst layer is selectively cross-linked while the cathode catalyst layer is not cross-linked. This has been found to provide structural stabilization of the CCM without loss of initial power value for a CCM without cross-linking.

Description

RELATED APPLICATIONS[0001]This application claims priority to U.S. provisional application Ser. No. 61 / 778,921, filed Mar. 13, 2013, and also claims priority to U.S. application Ser. No. 13 / 912,402, filed Jun. 7, 2013, which is a continuation-in-part application of U.S. application Ser. No. 13 / 154,056, filed Jun. 6, 2011, all of which are incorporated by reference herein in their entirety.FIELD OF THE INVENTION[0002]This invention relates to fuel cells and in particular alkaline membrane fuel cells and apparatus and methods of stabilizing the CCM structure during fuel cell operation.BACKGROUND[0003]The technology of alkaline membrane fuel cells (AMFCs) has been developed to date with OH-ion conducting polymers (“ionomers”) with a poly{hydrocarbon} backbone. Such ionomers require significant water uptake to achieve sufficient ionic conductivity. The structure and specification of an AMFC is illustrated in, for example, US 2010 / 0021777, entitled “Alkaline Membrane Fuel Cells and Appar...

AI Technical Summary

Benefits of technology

This approach achieves structural stabilization of the catalyst layer and membrane interface, maintaining initial power output and resistance over extended operation times without external water supply, while ensuring unhindered water and ion transport.

Problems solved by technology

As the level of water uptake increases—likely over 50% by weight—the ionomer typically loses mechanical integrity, resulting in morphological changes and, in some cases, overall disintegration which causes strong loss of cell performance.